Lower carboxylic acids and esters such as acetic acid and methyl acetate have been known as industrial chemicals for many years. Acetic acid is used in the manufacture of a variety of intermediary and end-products. For example, an important derivative is vinyl acetate which can be used as monomer or co-monomer for a variety of polymers. Acetic acid itself is used as a solvent in the production of terephthalic acid, which is widely used in the container industry, and particularly in the formation of PET beverage containers.
There has been considerable research activity in the use of metal catalysts for the carbonylation of alkyl alcohols, such as methanol, and ethers to their corresponding carboxylic acids and esters, as illustrated in equations 1-3 below:ROH+CO→RCOOH  (1)2ROH+CO→RCOOR+water  (2)ROR′+CO→RCOOR  (3)
Carbonylation of methanol is typically carried out in the liquid phase with a catalyst. However, there is a continuing need for a catalyst which can be used in a vapor phase carbonylation process for the production of carboxylic acids and their esters and in which the catalyst is maintained in the solid phase.